There seems to be a lot of confusion regarding components and terms for accessories and tools in this thread. The "keys" that have been pictured might be used to lightly twist fuzes into projectiles, but their intended purpose is to provide a shoulder on the ogive section of the projectile for the shipping tube to engage, so the projectile fuze doesn't get slammed into the end of the tube or anything else, if the shippind tube is dropped point-end down. They can also be found on fuzed 2.75 inch rocket warheads that have the fuzes cemented in place. They keep the pointy end of the warhead centered in the cardboard shipping tube and protect the fuze from impact. Since they are cheap metal and open-ended, they will spread out and fall out of the grooves on a fuze, if any type of torque is put on them. They are only present on warheads shipped in cardboard tubes, most often with fuzes installed, but also with plugs installed in the fuzewell.
Fuze wrenches are the tools used to install or remove fuzes from projectiles, and torque them in place before firing.
Fuze setters come a variety of types and are used to set the time from firing to fuctioning on time fuzes. They can be hand operated, battery powered, completely automatic, mechanical or electrical.